Real estate is rather different from the commodities markets, though: It's most definitely not a commodity (if you don't count things like mortgage-backed securities, anyway), and the markets are frighteningly illiquid. There are things like futures and options on real estate, but they operate very differently from your average put on hard white winter wheat.

There's an argument, not entirely (as far as I can tell) unreasonable, that at least some trading firms - the market makers - are benefitting the small folks in these markets. The argument goes that they do siphon profits out of the market, but it's mostly the profits of other financial firms. What they're ultimately nabbing is profits that come from information asymmetry, and that asymmetry usually benefits hedge funds more than farmers. So hedge funds make less money, yeah, but the impact on farmers is greater price stability, which is a benefit to them.

By extension, the implication is that, when hedge fund managers complain loudly about high frequency trading, it's crocodile tears.